In the related art, there is known a CMOS image sensor having a column type analog-to-digital conversion circuit (column type A/D conversion circuit) as an example of a solid-state imaging device. Image quality in the CMOS image sensor having the column type A/D conversion circuit may be degraded, for example, due to vertical line noise generated in each vertical line (column) or horizontal line noise generated in each horizontal line (row). The vertical line noise is principally generated due to unevenness of characteristics in each element of the A/D conversion circuit. The horizontal line noise includes noise generated during reset in the read operation for each horizontal line (reset noise).
As a technique for reducing vertical line noise or horizontal line noise, for example, there is known a technique of collectively subtracting an average of an output signal of an optical black (OB) portion from an output signal of an effective pixel portion for each vertical line and for each horizontal line. The effective pixel portion includes pixel cells having a photoelectric conversion element arranged in parallel and outputs an effective pixel signal depending on the light intensity. The OB portion includes pixel cells having an optically-shielded photoelectric conversion element arranged in parallel and outputs a black level signal representing a lowest gradation level. Since a component generating the vertical line noise or the horizontal line noise is equally contained in the effective pixel signal and the black level signal, the vertical line noise or the horizontal line noise can be reduced through the adding/subtracting process.
Recently, as the camera module becomes high resolution, and pixels become miniaturized, a defective portion (hereinafter, referred to as a “defect”) in a digital image signal caused by a failed pixel becomes an issue. If the average of the black level signal is collectively added/subtracted when the defect is generated in the OB portion, influence of the defect in the OB portion is collectively applied to the effective pixel signal, and the noise correction may be erroneously carried out. In the technique for suppressing influence of the defect generated in the OB portion in the related art, while erroneous noise correction caused by the defect can be alleviated, an effect of suppressing at least one of the vertical line noise and the horizontal line noise may be degraded.